Article: Age and geochemistry of contrasting peridotite types in the Dabie UHP belt, eastern China: Petrogenetic and geodynamic implications

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TitleAge and geochemistry of contrasting peridotite types in the Dabie UHP belt, eastern China: Petrogenetic and geodynamic implications
AuthorsZheng, JP1
Sun, M1
Griffin, WL1
Zhou, MF1
Zhao, GC1
Robinson, P1
Tang, HY1
Zhang, ZH1
KeywordsAge dating
Dabie UHP terrane
Geochemistry
North China mantle wedge
Peridotite PGE
Yangtze Neoproterozoic intrusion
Zircon Hf isotope
Issue Date2008
PublisherElsevier BV. The Journal's web site is located at http://www.elsevier.com/locate/chemgeo
CitationChemical Geology, 2008, v. 247 n. 1-2, p. 282-304 [How to Cite?]
DOI: http://dx.doi.org/10.1016/j.chemgeo.2007.10.023
AbstractThe Dabie ultrahigh-pressure (UHP) metamorphic belt, central China, contains two contrasting types of ultramafic-mafic complex. The Bixiling peridotite in the southern Dabie terrane contains abundant garnet (21-32 vol.%) and thus has high CaO +Al 2O 3 (9.94-15.3 wt.%). The peridotite also has high REE contents with flat REE patterns, high contents of S and other incompatible trace elements, together with low-Mg # olivine and pyroxene and low Ni and PGE contents. Zircons from this peridotite mostly have low Th/U ratios, interpreted to reflect a metamorphic origin, and give dominantly Triassic ages (ca. 210 Ma). Other zircons with high Th/U ratios give upper intercept ages of 745 Ma. Most zircons have positive e{open} Hf (+- 3.6 ∼ +- 8.1) values with depleted-mantle model ages (T DM) of 0.6-1.0 Ga (mean 0.8 Ga) and crustal model ages (T crust) of 0.8-1.4 Ga (mean 1.1 Ga). We interpret that the Bixiling complex was formed as cumulates in a Neoproterozoic asthenosphere-derived magma chamber in the continental crust, and was later carried to garnet-stable depths (ca. ∼ 4.4 GPa) during the subduction of the Yangtze Craton in the Triassic. In contrast, the Raobazhai peridotite in the northern Dabie terrane was metamorphosed at lower P/T conditions (i.e. 15 Kb and 1000 °C). All zircon grains from the peridotite yield Triassic ages (ca. 212 Ma) and have negative e{open} Hf values (- 16.6 ∼ - 3.2), Mesoproterozoic model ages (T DM = 1.0-1.5 Ga) and Paleoproterozoic crustal model ages (T crust = 1.5-2.3 Ga). The peridotite is enriched in LREE ((La/Yb) n ≈ 3.5), has high-Mg # olivine and pyroxene, high Ni and PGEs but low Pd/Ir (mean 3.0). It represents a highly refractory residue of partial melting (up to 18%) of primitive mantle, and is similar to the cratonic mantle xenoliths in Phanerozoic igneous rocks from the eastern North China Craton (e.g. Mengyin and Hebi areas). Negative Ce, Eu and HFSE anomalies in the peridotites suggest that their protolith was derived from the shallow part of the mantle wedge (e.g. plagioclase-stable field) of the North China Craton, and was pulled to a deeper level (e.g. spinel-stable field) during the subduction of the Yangtze Craton. The mantle wedge, like peridotitic xenoliths in the Jurassic Xinyang diatremes at the southern edge of the North China Craton, was metasomatised by fluids/melts released from the subducted continental crust. The fragments of this modified mantle wedge were incorporated into the Yangtze crust during its subduction. © 2007 Elsevier B.V. All rights reserved.
ISSN0009-2541
2011 Impact Factor: 3.518
2011 SCImago Journal Rankings: 0.172
DOIhttp://dx.doi.org/10.1016/j.chemgeo.2007.10.023
ISI Accession Number IDWOS:000253114500018
ReferencesReferences in Scopus
DC Field
Value
dc.contributor.authorZheng, JP
dc.contributor.authorSun, M
dc.contributor.authorGriffin, WL
dc.contributor.authorZhou, MF
dc.contributor.authorZhao, GC
dc.contributor.authorRobinson, P
dc.contributor.authorTang, HY
dc.contributor.authorZhang, ZH
dc.date.accessioned2010-09-06T06:43:09Z
dc.date.available2010-09-06T06:43:09Z
dc.date.issued2008
dc.description.abstractThe Dabie ultrahigh-pressure (UHP) metamorphic belt, central China, contains two contrasting types of ultramafic-mafic complex. The Bixiling peridotite in the southern Dabie terrane contains abundant garnet (21-32 vol.%) and thus has high CaO +Al 2O 3 (9.94-15.3 wt.%). The peridotite also has high REE contents with flat REE patterns, high contents of S and other incompatible trace elements, together with low-Mg # olivine and pyroxene and low Ni and PGE contents. Zircons from this peridotite mostly have low Th/U ratios, interpreted to reflect a metamorphic origin, and give dominantly Triassic ages (ca. 210 Ma). Other zircons with high Th/U ratios give upper intercept ages of 745 Ma. Most zircons have positive e{open} Hf (+- 3.6 ∼ +- 8.1) values with depleted-mantle model ages (T DM) of 0.6-1.0 Ga (mean 0.8 Ga) and crustal model ages (T crust) of 0.8-1.4 Ga (mean 1.1 Ga). We interpret that the Bixiling complex was formed as cumulates in a Neoproterozoic asthenosphere-derived magma chamber in the continental crust, and was later carried to garnet-stable depths (ca. ∼ 4.4 GPa) during the subduction of the Yangtze Craton in the Triassic. In contrast, the Raobazhai peridotite in the northern Dabie terrane was metamorphosed at lower P/T conditions (i.e. 15 Kb and 1000 °C). All zircon grains from the peridotite yield Triassic ages (ca. 212 Ma) and have negative e{open} Hf values (- 16.6 ∼ - 3.2), Mesoproterozoic model ages (T DM = 1.0-1.5 Ga) and Paleoproterozoic crustal model ages (T crust = 1.5-2.3 Ga). The peridotite is enriched in LREE ((La/Yb) n ≈ 3.5), has high-Mg # olivine and pyroxene, high Ni and PGEs but low Pd/Ir (mean 3.0). It represents a highly refractory residue of partial melting (up to 18%) of primitive mantle, and is similar to the cratonic mantle xenoliths in Phanerozoic igneous rocks from the eastern North China Craton (e.g. Mengyin and Hebi areas). Negative Ce, Eu and HFSE anomalies in the peridotites suggest that their protolith was derived from the shallow part of the mantle wedge (e.g. plagioclase-stable field) of the North China Craton, and was pulled to a deeper level (e.g. spinel-stable field) during the subduction of the Yangtze Craton. The mantle wedge, like peridotitic xenoliths in the Jurassic Xinyang diatremes at the southern edge of the North China Craton, was metasomatised by fluids/melts released from the subducted continental crust. The fragments of this modified mantle wedge were incorporated into the Yangtze crust during its subduction. © 2007 Elsevier B.V. All rights reserved.
dc.description.natureLink_to_subscribed_fulltext
dc.identifier.citationChemical Geology, 2008, v. 247 n. 1-2, p. 282-304 [How to Cite?]
DOI: http://dx.doi.org/10.1016/j.chemgeo.2007.10.023
dc.identifier.doihttp://dx.doi.org/10.1016/j.chemgeo.2007.10.023
dc.identifier.epage304
dc.identifier.hkuros144279
dc.identifier.isiWOS:000253114500018
dc.identifier.issn0009-2541
2011 Impact Factor: 3.518
2011 SCImago Journal Rankings: 0.172
dc.identifier.issue1-2
dc.identifier.openurl
dc.identifier.scopuseid_2-s2.0-37549059571
dc.identifier.spage282
dc.identifier.urihttp://hdl.handle.net/10722/72578
dc.identifier.volume247
dc.languageeng
dc.publisherElsevier BV. The Journal's web site is located at http://www.elsevier.com/locate/chemgeo
dc.publisher.placeNetherlands
dc.relation.ispartofChemical Geology
dc.relation.referencesReferences in Scopus
dc.rightsChemical Geology. Copyright © Elsevier BV.
dc.subjectAge dating
dc.subjectDabie UHP terrane
dc.subjectGeochemistry
dc.subjectNorth China mantle wedge
dc.subjectPeridotite PGE
dc.subjectYangtze Neoproterozoic intrusion
dc.subjectZircon Hf isotope
dc.titleAge and geochemistry of contrasting peridotite types in the Dabie UHP belt, eastern China: Petrogenetic and geodynamic implications
dc.typeArticle
Author Affiliations
  1. China University of Geosciences